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An FMA operation (A*B + C) can be done in 5 cycles on intel's Haswell architecture. Can anyone explain what happens in each of the 5 cycles? For a Multiply I know that the stages are as follows:

  1. Seperate Mantissa and Exponent
  2. Multiply Mantissa
  3. Multiply Exponent
  4. Normalize the results
  5. Insert Sign

But I have been unable to find the pipeline stages for the FMA operation

Edit: It seems that the above is not the actual method used in the pipeline for Mult (Thanks to @EOF, and @harold for the headsup)

Amir
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    What makes you think that those are the pipeline stages for multiplication? – EOF May 01 '17 at 21:42
  • @EOF Ok maybe this is not the exact algorithm used on Haswell. Can you please let me know if there is any reference that explain the pipeline stagesfor the multiplication, addition, and fused multiply add on Haswell (assuming it is not a trade secret) – Amir May 01 '17 at 23:15
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    It's probably secret but it's definitely not as you showed, that pipeline makes no sense. – harold May 02 '17 at 15:31
  • @harold Ok I see thanks – Amir May 02 '17 at 16:53

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